Methods for controlling one or more positioning actuators and devices thereof

• US 8,466,637 B2
• Filed: 07/20/2010
• Issued: 06/18/2013
• Est. Priority Date: 07/20/2010
• Status: Active Grant

• Current Assignee: New Scale Technologies Incorporated
• Original Assignee: New Scale Technologies Incorporated
• Inventors: Guidarelli, Thomas, Henderson, David A.
• Primary Examiner(s): DUDA, RINA I
• Application Number:
  US12/840,009
• Publication Number:
  US 20120019185A1
• Time in Patent Office: 1,064 Days
• Field of Search: 310/311, 310/323.17, 310/323.18, 310/323.21, 318/118, 318/128, 318/282, 318/286, 318/466, 318/461, 318/468
• US Class Current: 318/118
• CPC Class Codes: G03B 15/00 Special procedures for taking photographs; Apparatus therefor
• CPC Class Codes: G05B 19/40 Open loop systems, e.g. using stepping motor
• CPC Class Codes: G05B 19/401 characterised by control arrangements for measuring, e.g. calibration and initialisation, measuring workpiece for machining purposes G05B19/19 takes precedence
• CPC Class Codes: G05B 2219/42108 Open loop for positioning, closed loop for calibration
• CPC Class Codes: H02N 2/062 Small signal circuits; Means for controlling position or derived quantities, e.g. for removing hysteresis
• CPC Class Codes: H02N 2/067 generating drive pulses

Abstract

A method, computer readable medium, and apparatus for controlling a moveable element includes generating and providing with a control device one or more driving signals to one or more positioning actuators to move the moveable element towards a target position based on a target travel distance and a calibration value. The control device determines when a post-movement position of the moveable element is outside of a tolerance range of the target position. The control device recalibrates the calibration value when the post-movement position is determined to be outside of the tolerance range. The control device repeats the generating, the determining, and the recalibrating as open loop steps until the post-movement position is within the tolerance range or until a limit, if any, on attempts is reached.

Claims

1. A method for controlling a moveable element, the method comprising:

generating and providing with a control device one or more driving signals to one or more positioning actuators to move the moveable element towards a target position based on a target travel distance and a calibration value;

determining with a position sensor and the control device when a post-movement position of the moveable element is outside of a tolerance range of the target position;

determining with the control device when a current position of the moveable element has overshot the target position as the one or more positioning actuators move the moveable element towards the target position;

recalibrating with the control device the calibration value when the post-movement position is determined to be outside of the tolerance range;

resetting with the control device the target travel distance when the current position is determined to has overshot the target position, wherein the generating and providing is based on the target travel distance after the resetting and the calibration value after the recalibrating; and

repeating with the control device the generating, the determining, the determining, the recalibrating and the resetting as open loop steps until the post-movement position is within the tolerance range.

2. The method of claim 1 further comprising:

determining with the control device the target travel distance based on a starting position and the target position; and

determining with the control device the calibration value initially based on the determined target travel distance before the generating and providing.

3. The method of claim 1 further comprising setting with the control device a direction of motion based on a starting position and the target position for the moveable element, wherein the generating and providing one or more driving signals is further based on the determined direction of motion.

4. The method of claim 1 further comprising:

determining with the control device a current position of the moveable element as the one or more positioning actuators move the moveable element towards the target position based on the generated one or more driving signals;

determining with the control device when the current position has overshot the target position as the one or more positioning actuators move the moveable element towards the target position; and

terminating with the control device the generating and providing the one or more driving signals when the current position is determined to have overshot the target position.

5. The method of claim 1 further comprising waiting for a first settling period of time with the control device before the determining when the post-movement position of the moveable element is outside of the tolerance range of the target position.

6. The method of claim 1 wherein the recalibrating further comprises:

determining with the control device when the calibration value after the recalibrating is outside a set operating range;

adjusting with the control device a velocity control value when the calibration value after the recalibrating is determined to be outside the set operating range;

readjusting with the control device the calibration value after the recalibrating based on the adjusted velocity control value.

7. The method of claim 1 further comprising terminating with the control device the generating and providing when a change limit has been reached.

8. A computer readable medium having stored thereon instructions for controlling a moveable element comprising machine executable code which when executed by at least one processor, causes the processor to perform steps comprising:

generating and providing one or more driving signals to one or more positioning actuators to move the moveable element towards a target position based on a target travel distance and a calibration value;

determining when a post-movement position of the moveable element is outside of a tolerance range of the target position;

determining when a current position of the moveable element has overshot the target position as the one or more positioning actuators move the moveable element towards the target position;

recalibrating the calibration value when the post-movement position is determined to be outside of the tolerance range;

resetting the target travel distance when the current position is determined to has overshot the target position, wherein the generating and providing is based on the target travel distance after the resetting and the calibration value after the recalibrating; and

repeating the generating, the determining, the determining, the recalibrating and the resetting as open loop steps until the post-movement position is within the tolerance range.

9. The medium of claim 8 further comprising:

determining the target travel distance based on a starting position and the target position; and

determining the calibration value initially based on the determined target travel distance before the generating and providing.

10. The medium of claim 8 further comprising setting a direction of motion based on a starting position and the target position for the moveable element, wherein the generating and providing one or more driving signals is further based on the determined direction of motion.

11. The medium of claim 8 further comprising:

determining a current position of the moveable element as the one or more positioning actuators move the moveable element towards the target position based on the generated one or more driving signals;

determining when the current position has overshot the target position as the one or more positioning actuators move the moveable element towards the target position; and

terminating the generating and providing the one or more driving signals when the current position is determined to have overshot the target position.

12. The medium of claim 8 further comprising waiting for a first settling period of time before the determining when the post-movement position of the moveable element is outside of the tolerance range of the target position.

13. The medium of claim 8 wherein the recalibrating further comprises:

determining when the calibration value after the recalibrating is outside a set operating range;

adjusting a velocity control value when the calibration value after the recalibrating is determined to be outside the set operating range;

readjusting the calibration value after the recalibrating based on the adjusted velocity control value.

14. The medium of claim 8 further comprising terminating the generating and providing when a change limit has been reached.

15. A positioning system for a moveable element, the system comprising:

at least one position sensor for monitoring a position of the moveable element;

drive signal generation device;

one or more positioning actuators coupled to the drive signal generation device and operatively coupled to the moveable element; and

a control device coupled to the position sensor and the drive signal generation device, the control device comprising one or more processors and a memory coupled to the one or more processors, the one or more processors configured to execute programmed instructions stored in the memory comprising;

generating and providing one or more driving signals to one or more positioning actuators to move the moveable element towards a target position based on a target travel distance and a calibration value;

determining when a post-movement position of the moveable element is outside of a tolerance range of the target position;

determining when a current position of the moveable element has overshot the target position as the one or more positioning actuators move the moveable element towards the target position;

recalibrating the calibration value when the post-movement position is determined to be outside of the tolerance range;

resetting the target travel distance when the current position is determined to has overshot the target position, wherein the generating and providing is based on the target travel distance after the resetting and the calibration value after the recalibrating; and

repeating the generating, the determining, the determining, the recalibrating and the resetting as open loop steps until the post-movement position is within the tolerance range.

16. The system of claim 15 wherein the one or more processors is further configured to execute programmed instructions stored in the memory further comprising:

determining the target travel distance based on a starting position and the target position; and

determining the calibration value initially based on the determined target travel distance before the generating and providing.

17. The system of claim 15 wherein the one or more processors is further configured to execute programmed instructions stored in the memory further comprising setting a direction of motion based on a starting position and the target position for the moveable element, wherein the generating and providing one or more driving signals is further based on the determined direction of motion.

18. The system of claim 15 wherein the one or more processors is further configured to execute programmed instructions stored in the memory further comprising:

determining a current position of the moveable element as the one or more positioning actuators move the moveable element towards the target position based on the generated one or more driving signals;

determining when the current position has overshot the target position as the one or more positioning actuators move the moveable element towards the target position; and

terminating the generating and providing the one or more driving signals when the current position is determined to have overshot the target position.

19. The system of claim 15 wherein the one or more processors is further configured to execute programmed instructions stored in the memory further comprising waiting for a first settling period of time before the determining when the post-movement position of the moveable element is outside of the tolerance range of the target position.

20. The system of claim 15 wherein the one or more processors is further configured to execute programmed instructions stored in the memory for the recalibrating further comprises:

determining when the calibration value after the recalibrating is outside a set operating range;

adjusting a velocity control value when the calibration value after the recalibrating is determined to be outside the set operating range;

readjusting the calibration value after the recalibrating based on the adjusted velocity control value.

21. The system of claim 15 wherein the one or more processors is further configured to execute programmed instructions stored in the memory further comprising terminating the generating and providing when a change limit has been reached.